Transparent plastic materials are frequently used in articles that require visibility and clarity through the materials. Examples of such articles include optical lenses, goggles, face shields, face plates for helmets, glazings used as windows in buildings, and glazings used as windshields or windows in buses, airplanes, and other transportation vehicles. However, transparent plastic materials tend to be soft and scratch or mar quite easily, which leads to reduced visibility and clarity through the transparent article.
Coatings have been used to help maintain visibility and clarity through the transparent plastic materials by providing a protective, abrasion-resistant layer over the substrate. Protective, abrasion resistant coatings are typically applied to the transparent plastic material in liquid form and then are cured to form the protective coating. The polymeric components of the coating composition crosslink during the curing process to harden and form the abrasion-resistant, protective coating.
Abrasion resistance and flexibility in organosiloxane protective coatings generally share an inverse relationship. Abrasion resistance in the organosiloxane coating correlates to the hardness of the coating. A harder coating provides a more abrasion-resistant coating than a comparably less hard coating. However, harder organosiloxane coatings are less flexible.
Disclosed herein are UV curable organosiloxane coating compositions that provide both abrasion resistance and flexibility in the cured coating.